Aromatic and pleasant tasting de-nicotinized tobacco and method of producing same



United States P m- AROMATIC AND PLEASANT TASTING DE-NICO- TINIZEDTOBACCO AND METHOD OF PRODUC- lNG SAME Heinz Thienemann, Beuel, andPeter Krug, Munich, Germany, assignors to Dr. Plate, G. m. b. H.,Chemische Fabrik, Bonn, Germany No Drawing. Application July 1, 1955Serial No. 519,657

22 Claims. (Cl. 131-17) The present inventionrelates to a tobacco havingreduced nicotine content, and especially to such a tobacco which isaromatic and pleasant tasting as well as to a method for the productionof such tobacco.

Various methods are known for the production of nicotine free tobacco ora tobacco with reduced nicotine content, in which methods the nicotinemay be recovered. It is possible to use a method based either on theprinciple of direct solvent extraction of nicotinecompounds wherebysoluble compounds will be washed out, or on the principle of leachingwith an alkaline aqueoussolution which depends upon a chemical reactionto break down insoluble compounds which, after such break down, areWashed out. Methods based on each .of these principles have beenmodified to include steps used in methods based on the other principle.According to the variations in the method used, different amounts ofnicotine will be recovered. Usually when a process basedon the principleof solvent extraction withoutany modification is used, the extraction ofnicotine will not proceed to a suflicient extent whereas when substancesare used which react chemically with tobacco as is true in leaching, agreater quantity of nicotine will be removed, but at the same timeundesirable damage to the tobacco will occur. For this reason it hasheretofore been very diflicult to obtain a good tobacco with agreeablesmoking characteristics, which tobacco has reduced nicotine content.Where good smoking characteristics have heretofore been obtained, thishas been at the cost of insuflicient nicotine removal.

We have found it possible to produce an aromatic and pleasant tastingtobacco with reduced nicotine content, providing that thedenicotinization is carried out in the presence of a quantity of analkalizing substance chemically corresponding in quantity to the amountof nicotine which is bound to phosphoric acid. By restricting the amountof the chemical reactant in leaching tothat quantity which has beenanalytically determined as that quantity necessary to treat the nicotinebound to phosphoric acid, it is possible to prevent damage ofthe-tobacco tozbe treated, and at he. same time. to carry thedenicotinization as far as desired. a

We have found that a portion of the nicotine in tobacco is always boundto phosphoric acid, the resultingsalt or salts being insoluble in water.In research, in studying the effect of varying quantities of phosphoricacid on the process of extraction, certain principles were discovered.

With equal total nicotine content, but different content of phosphoricacid, meaning that varyingquantities of coti oc urr d nt e o of e alt ofthis add a greater quantity of nicotine is removed by asimple sol-2,822,396 l atentecl Feb. 4%, 19 58:

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vent reaction when less phosphoric acid is present. On

Based upon the results which we have found, denicotinization can beexecuted with highest yield of'nic'otine and with best care for thetobacco whenan alkaline substance is added corresponding in amount tothe content of nicotine bound to phosphoric acid, the addition beingmade either before or simultaneously with the extraction. By thisaddition of a certain amount of alkaline substance, it is possible toremove from the tobacco the nicotine previously non-extractable, i. e.the nicotine bound to phosphoric acid, while, by avoiding the presenceof an excess of the alkaline substance which is used, damage to thetobacco will be avoided.

The quantity of alkaline substances necessary in order to release thenicotine bound to phosphoric acid can be calculated. In doing so, it isnecessary to determine first by chemical analysis :the content ofphosphoric acid and total nicotinecontent in the particular lot oftobacco involved. The analytical techniques necessary for suchdetermination are well known-and do not form part of the presentinvention. For example, phosphoric acid content can be determined byprecipitating the phosphate with ammonium molybdate, from a solutionprepared by dissolving with nitric acid an ash prepared-from a tobaccosample, the solution being diluted with water. The precipitate is thendissolved with sodium hydroxide solution, and this titrated withhydrochloric acid. In like manner, nicotine can be determined by knowntechniques, a precipitate first being prepared which is'soluble inwater, and the aqueous solution of this precipitate being titrated witha caustic solution. From these values there is calculated the nicotinebound to phosphoric acid by means of the valences. and the secondarynicotine phosphate are possible-with the same content of phosphoricacid. Onemay obtain, therefore, two different values for bound nicotine,i. e. firstly a lower value for the primary salt, and secondly a highervalue for the secondary salt. Because of the native character of thetobacco plant, there are probably formed both types of combination, andin most cases, one will find mixtures of the salts. The quantity ofalkaline substances added is therefore increased or decreased dependingon the nature of the phosphates present in a given tobacco.

In the case of the presence of the primary salt, the quantity ofalkaline substances to be added is'smaller than in the case of thesecondary salt. In the process of ex traction, an addition of alkalinesubstance corresponding to the primary salt will be suflicient in mostcases, as

the remaining nicotine content will then be below the limit of theso-called nicotine-poor tobaccos. It is also possible to exactlydetermine by chemical analysis whether in an individual case moreprimary-or more secondary nicotine salt is present, and then to exactlycalculate the necessary quantity of alkaline substance.v

ing nicotine content after a solvent extraction without Theoretically,the primary any addition of an alkaline substance, i. e. beforeleaching. (Nora-The values for total nicotine content, for content ofphosphoric acid, and for nicotine remaining before leaching weredetermined by chemical analysis, while the values for amount of nicotinebound to the respective salts were calculated.)

As may be seen from these experimental results, generally with highercontent of phosphoric acid relative tov the total amount of nicotineinitially present, the greater is the proportionate amount of nicotineremaining after the extraction and before leaching. Furthermore, it maybe seen that the amount of nicotine remaining after extraction isgenerally within the limits calculated for the nicotine bound in theprimary and secondary salts. The values show that it is possible bydetermining the content of phosphoric acid, to establish the mostfavorable extent to which an extraction may be carried before anyaddition of alkaline substances. This has been impossible according tohitherto existing knowledge.

The selective nicotine extraction according to the present invention, inwhich a quantity of alkaline substances corresponding to the nicotinebound to phosphoric acid is addedymay be carried out with organicsolvents or solvent mixtures as well as with water. For a higher yield,and a generally more careful treatment of the tobacco, it is morefavourable to carry out the extraction not with the solvents or solventmixtures alone, but in the presence of a certain amount of water. By theuse of a certain quantity of water, it is possible to prevent thedehydration of the tobacco which usually occurs with the solventextraction. By the use of water not only is embrittling of the tobaccoprevented, but also the necessary opening up of the tobacco plant tissuecells is assured. Under such conditions, the solvent can enter into thecells. Furthermore, the water is a suitable carrier of the alkalinesubstance because this substance is in most cases more easily soluble inwater than in organic solvents. The addition of water to the organicsolvent or organic solvent mixture favors a selective nicotineextraction for a further reason; to wit, that a co-extraction of thewaxes, resins and volatile oils will for the most part be avoided.Therefore, it is of special importance to provide a permanent saturationof the solvents or solvent mixtures respectively with water, for onlythen, an extensive extraction of the nicotine, together with a carefultreatment of the tobacco, will be obtained, and this is indispensablefor the production of smoking tobacco with reduced nicotine content. Themaintenance of the saturation with water can be obtained by providing areservoir of water, on the bottom of the solvent collecting-vessel.

ferent ways. For example, one can spread the alkaline substance on thetobacco before the extraction is carried out. One can also combine thetreatment by alkaline or solvent mixtures, since a preliminaryextraction as well The addition of alkaline reagents can be done indif-- reagent with a water vapour treatment. ThlS combined: method issuitable in an extraction using organic solventmust be highly insolublein water.

tity of alkaline substances corresponding to the content of nicotinebound to phosphoric acid to the water which is necessary for thesaturation of the organic solvent. The alkaline substance may also beadded to the reservoir of water on the bottom of the solventcollecting-vessel.

As alkaline substances, there are preferably used those which will notappreciably influence the pH, even at higher concentrations. They mustbe, however, of a higher alkalinity than the nicotine, so that achemical release will be possible. Very much suited are ammonia, or suchproducts which release ammonia, such as ammonium bicarbonate.

' As already mentioned, the extraction of the nicotine from the tobaccocan also be carried out by leaching with water to which a quantity ofalkaline substances corresponding to the content of nicotine bound tophosphoric acid has beenadded. Here again, it is possible to carry outthe extraction in such a manner that the tobacco will suffer no damage,and will be entirely suited for the production of smoking tobacco. Inorder to give the tobacco a full flavor, it is recommended that thenicotine in the extract obtained by the leaching be removed from theextract to produce a suitable concentrate of nicotine-free extract, thedenicotinized tobacco being thereafter treated with this concentrate.The process of concentration which is necessary for the manufacture ofthe extract is preferably carried out in vacuum, in order to avoid anydamage to the ingredients therein.

The denicotinization of the extract can be carried out by means ofsuitable solvents, such as trichlorethylene, which may be added to theaqueous extraction product either before or after evaporation tocondense such product. Simply by shaking extraction product to whichsolvent has been added, the latter will take up the nicotine, and thenicotine bearing solvent may then be removed from the extractionproduct. On the one hand, a solvent for such nicotine extraction musthave a very good solubility for the nicotine, but on the other hand,

The latter requirement is important for otherwise the process ofevaporation will be subject to considerable interruption and there mayalso be considerable loss of solvent, when the solvent for nicotine isadded to the extraction product before evaporation to condense thelatter.

The produced extract concentrate may be introduced to the treatedtobacco either in nicotine free from, or with a certainnicotine content.Through control of the leachingo'n the one hand, and through an additionof either a nicotine free extract concentrate, or an extract concentratewith'a certain nicotine content, one can obtain a tobacco having an.entirely controlled nicotine content, i. e. one can produce eithernicotine free smoking tobacco, or such tobacco having a little nicotinecontent.

. In order to enhance'the taste of the smoking tobacco, one can addcertain arornatic substances or extracts to the concentrate obtainedfrom the tobacco according to the present invention, which concentrateis to be introduced into the tobacco after the leaching is carried out.These aromatic substances or extracts may be of natural or syntheticorigin. Furthermore, it is possible to acidity the concentrate obtainedfrom the tobacco with such acids which are usually present in thetobacco. As accordingto the found results,'the prosphoric acid is ofconsiderable importance, it is suitable to use it for the statedpurpose. 1 'F For further improvement of the aromatic properties,-

it has proved favorable to submit the obtained denicotinized tobacco toa further aromatization in vacuum.

EXAMPLE I American Virginia tobacco having a nicotine content of 2.50%was extracted with ethyl acetate saturated with, water, with theaddition of the quantity of an alkaline sub stance -correspondinga.tothe content of nicotine bound to phosphoric acid. Thecontent ofphosphoric 'acid-was 1.07%. This value corresponds to 1.77% boundnicotine in the form of secondary salt. Therefore, there had to beapplied 1.6% ammonium bicarbonatewhich was added to the water necessaryforthe saturation of the' ethyl acetate. The applied ratio of ethylacetate to water was 5.521. The weight of ethyl acetate was fourteentimes the weight of tobacco.

The extraction was carried out according to the Soxhlet method. After anextraction of 3 hours, the remaining nicotine content'was 0.58%. Thetobacco so produced with reduced nicotine content was aromatized invacuum as follows: 2% (calculated in the weight. of tobacco) of awatery-alcoholic flavor (with 30% alcohol content) was allowed to flowinto an evacuatable vessel containing the tobacco, at a pressure of 25mm. Hg. The vacuum was maintained for thirty minutes, in order to obtainan equal .distribution of the aromatic substances. By the treatment inthe vacuum, the flavoring agent is more intimately combined with thetobacco, than would be the case were the agent sprayed on the tobacco,as would be done normally. The aromatized tobacco so obtained withreduced nicotine'content was cut and processed into smoking tobacco. Itwas extremely mild, and showed no loss of the properties of a Virginiatobacco.

EXAMPLE II American Virginia tobacco having a nicotine content of 22%and a content of phosphoric acid of 0.82% was spread with the quantityof ammonium bicarbonate (1.36%) which is necessary for the releaseof thenicotine bound in phosphoric acid, this tobacco having previously beensubmitted to a water vapor treatment. The extraction was carried outwith ethyl acetate saturated with water according to the Soxhlet method,a reservoir of water being maintained in the solvent collecting: vessel.The remaining nicotine content was 0.39% after an extraction of 2 hours.When determining the cx tracted nicotine in the solvent, there werefound 93.8% of the total quantity in the reservoir of water.

The resulting tobacco with reduced nicotine content was processed intosmoking tobacco. It was found that the aroma of the original tobacco hadnot essentially been changed.

EXAMPLE III American Virginia tobacco having a nicotine content of 2.76%and a content of phosphoric acid of 0.93% was subjected to a water vaportreatment before the extraction was carried out; At the same time, therewas applied as much ammonia as was made necessary with regard to theamount of primary nicotine salt present. For this, the water vaporproducer was filled with ammonium bicarbonate. The tobacco treated insuch a manner was leached with ethyl acetate according to the Soxhletmethod, with maintenanceof a reservoir of water. The quantity of ethylacetate used was tenfold the weight of tobacco used. The remainingnicotine content was 0.43% after an extraction of 4 hours.

EXAMPLE IV American Virginia tobacco having a nicotine content of 2.94%was leached with a sixfold quantity by weight of water. The leaching wascarried out in two steps, at a temperature of 45 C. in the first step,and 55 C. in the second step. In the second step there was added thequantity of ammonium bicarbonate (1.69%) corresponding to the content ofphosphoric acid (1.02%). The time of leaching was one hour per step. Theextracts obtained in the two steps were consolidated and the nicotineremoved from the extract by a threefold shaking with trichlorethylene.The remaining nicotine content in the extract was 0.2 g. per litre. Thenicotine free extract was compressed to a concentrate by means of avacuum circulation evaporator at a pressure of120 mm. Hg, the quantityof the concentrate being 28% of the original weight of'tobacco. Throughan addition of citric acid the pH of the extract concentrate wasadjusted to 5.8.- In -this adjustment, the extract concentrate wasplaced uponuthe tobacco which had'meanwhile been dried. After agstor ingof two hours, the sauced tobacco was cut,- and then roasted; h p

The so obtained tobacco with aremaining nicotinecontent of 0.53% wasworked up into cigarettes. The ciga rettes were aromatic and bettertastingwthan those of the untreated tobacco.

EXAMPLE V Similar'tmExarnple 4,' an'"Arnerican"Virginia tobacco having'anicotine 'contentof' 3.26%"wasleached in two steps of one houreach'at'temperatures of 45 C. and 55 C. respectively. The. secondleaching was executed with an addition of 1.5%' ofbicarbonatecorresponding. tothe secondary nicotine salt bound to phosphoric acid,.under consideration of a content of phosphoric acid of 0.91%.

In contrast toExample-IV, the tobacco was subjected, however, to a watervapour treatment before being leached. Bythis, there was obtained a morefavorable behavior ofthe tobacco when-placed in the leaching vessel, i.e; thebreaking was considerably reduced, and on the. other hand, thetake-up of water through the cells already swelled was quicker.

From the'extract obtained through the leaching, there was produced by,evaporation under vacuum a reduction to half of thevolume ofa so-calledintermediate concena trate. This was shaken three times withtrichlorethylene at'a pH of 8.8 in order to remove the nicotine. Thenearly'nicotine' free intermediate concentratewas further evaporated inthe vacuum. The obtained 'final-concen trate corresponded to 24% of theoriginalweight of'tobacco. The nicotine content in the final concentratewas 10.5 g. per .kg. After an acificiation' with phosphoric acid inorder to obtain a pH of 5.9, further'7.5"g. of pure nicotine were addedper kg.'final concentrate, so thatafter having executed the saucing-thetreated tobacco was adjusted to a nicotine content of0.6%

From the foregoing, there is to be seen thatwehave produced mild andpleasant tasting tobaccos with reduced nicotine content without anysutfering-of-the aromatic properties.

Examples of successful extractions of nicotine have been given above.There now followexamples of tures which have been used in thearomatization of "dc nicotinized tobacco. It will be noted thatin'boththe mixtures given, an important ingredient is'the extractalready referred to in the heretofore-described process of.

denicotinization by leaching with water to which alkaline substanceshave been added and where extract is specified in the followingexamples, it is such extract'whichis' meant. following examples, what ismeant is a cleariglucose syrup obtainedfrom starch-flour by reactionwith sulfuric acid. The root'tar extract specifiedin'thefollowingexamples is prepared by making a solution of 10 partsroottar obtained from the root of conifers with parts of 65% alcohol.This solution is distilled until 70 parts have distilled over, whereuponthe distillate is then mixed with 30 parts of 65 alcohol and filtered.

EXAMPLE VI Where starch sugar syrup" is specified in the" Aromatizationmaking use of these mixtures may be carried out by spraying them ontothe dried denicotinized tobacco.

Having now particularly described and ascertained the nature of our saidinvention, and in what manner the same is to be performed, we declarethatzwhat we claim is:

l. A method for the production of a tobacco product from untreatedtobacco containing insoluble nicotine phosphoric acid salts, comprisingthe steps of first quantitatively determining the content of phosphoricacid in said untreated tobacco, and subsequently treating said tobaccowith a basic material capable of displacing the nicotine from the saidsalts, the amount of said basic material added being substantially equalto that amount required to combine in stoichiometric proportion with thephosphoric acid in said salts whereby nicotine is displaced therefrom,and the removal of nicotine so displaced from said tobacco.

2. A method as claimed in claim 1 wherein said basic material iscontained in a liquid.

3. A method as claimed in claim 1 wherein the said basic material isammonia.

4. A method as claimed in claim 1 wherein the said basic material is anammonia derivative.

5. A method as claimed in claim 2 wherein said liquid is a non-aqueoussolvent saturated with water.

6. A method as claimed in claim 5 wherein said basic material is addedto the water necessary for the saturation of said non-aqueous solvent.

7. A method as claimed in claim 5 wherein a reservoir of water ismaintained in the solvent vessel during removal of displaced nicotinefrom said tobacco.

8. A method as claimedin claim 2 wherein said liquid is ethyl acetatesaturated'with water.

9. A method as claimed in claim 2 wherein said liquid is water.

10. A method as claimed in claim 1 wherein the treatment with said basicmaterial is carried out prior to the removal of displaced nicotine fromsaid tobacco. I

11. A method as claimed in claim 1 wherein the treatment with said basicmaterial iscarried out simultane ously with the removal of displacednicotine from said tobacco.

subsequent step of adding to the said tobacco product a nicotine-freeextract prepared from the residue obtained upon removal ofnicotinedisplaced from said tobacco.

15. A method as claimed in claim 14 wherein the residue obtained is aliquid, and said nicotine-free extract is prepared by evaporating saidliquid under reduced pressure and by removing the nicotine from saidliquid by adding to said-liquid a reagent in which the nicotine issoluble, but which reagent is substantially insoluble in water, andthereafter removing said reagent after said nicotine has dissolvedtherein.

16. A method as claimed in claim 1 including the subsequent step ofadding to the said tobacco product an extract prepared from the residueobtained upon removal of nicotine displaced from said tobacco, a portionof the nicotine being removed from said residue.

17. A method as claimed in claim 14 in which phosphoric acid is added tosaid extract prior to the addition thereof to the said tobacco product.

18. A method as claimed in claim 14 in which aromatic substances areaddedto said extract prior to the addition thereof to the said tobaccoproduct.

19. A tobacco'product prepared from untreated tobacco containinginsoluble nicotine phosphoric acid salts, from which untreated tobacconicotine has been removed by use of an amount of basic materialsufficient only to combine in stoichiometric proportion with thephosphoric acid in the said nicotine phosphoric acid salts.

20. A tobacco product prepared from untreated tobacco containingins-olublenicotine phosphoric acid salts, from which untreated tobacconicotine has been extracted by use of a solution of water containing anamount of basic material sufiicient only to combinein stoichiometricproportion with the phosphoric acid in the said nicotine phosphoric acidsalts.

21. A tobacco product as claimed in claim 20 to which has been added anextract concentrate prepared from said solution after the removal ofsaid solution from said tobacco product, a portion of the nicotinehaving first been removed from said solution.

22. A tobacco product as claimed in claim 19 which has been renderedaromatic by the addition of aromatic substances.

References Cited in the file of this patent UNITED STATES PATENTS246,975 Philips Sept. 13, 1881 802,487 Wimmer Oct. 24, 1905 999,674Sartig Aug. 1, 1911 1,577,768 Smith Mar. 23, 1926

1. A METHOD FOR THE PRODUCTION OF A TOBACCO PRODUCT FROM UNTREATEDTOBACCO CONTAINING INSOLUBLE NICOTINE PHOSPHORIC ACID SALTS, COMPRISINGTHE STEPS OF FIRST QUANTITATIVELY DETERMINING THE CONTENT OF PHOSPHORICACID IN SAID UNTREATED TOBACCO, AND SUBSEQUENTLY TREATING SAID TOBACCOWITH A BASIC MATERIAL CAPABLE OF DISPLACING THE NICOTINE FROM THE SAIDSALTS, THE AMOUNT OF SAID BASIC MATERIAL ADDED BEING SUBSTANTIALLY EQUALTO THAT AMOUNT REQUIRED TO COMBINE IN STOICHIOMETRIC PROPORTION WITH THEPHOSPHORIC ACID IN SAID SALTS WHEREBY NICOTINE IS DISPLACED THEREFROM,AND THE REMOVAL OF NICOTINE SO DISPLACED FROM SAID TOBACCO.